A fungal strain of Trichoderma having strong chitinolytic activity was isolated from field soil enriched with crabshell for several years. Based on 5.8S rRNA, partial 18S, 28S rRNA genes, ITS1, ITS2 sequence analysis and morphological characteristics, the fungus was identified as Trichoderma asperellum and named as Trichoderma asperellum T-5 (TaT-5). The fungus released lytic enzymes such as chitinase and -1, 3-glucanse, and produced six antifungal substances in chitin broth medium. To demonstrate the protective effect of TaT-5 against damping-off in cucumber plant caused by Rhizoctonia solani, TaT-5 culture broth (TA), chitin medium (CM) and distilled water (DW) were applied to each pot at 10 days after sowing, respectively. Then, the homogenized hyphae of R. solani were infected to each pot at 1 week after TaT-5 inoculation. During experimental period, fresh weight of shoot and root in cucumber plant more increased at TA treatment compared to other treatments. PR-proteins (-1, 3-glucanase and chitinase) activities in cucumber leaves markedly increased at CM and DW treatments, but the activity slightly increased and then decreased at TA treatment at 3 days after infection of R. solani. The activity of PR-proteins activities in cucumber roots at all treatments decreased with time where the degree of decrement was more alleviated at TA treatment than CM and DW. These results suggest that the lytic enzymes (chitinase and -1, 3-glucanse) and antifungal substances produced by TaT-5 can reduce the pathogenic attack by R. solani in cucumber plants.

This study was carried out to investigate the changes in soil chemical properties and yields of crops by ricesoybean rotation cropping system at silt loam soil. There were 4 rotation cropping systems; continuous rice cultivation, annual, biennial and triennial rotation of soybean and rice. There were little change in pH, organic matter, Ca2+ and K+ contents with decrease in available phosphate content in the continuous rice cropping. The cropping system of soybean-rice caused to increase in available P2O5, K+ and Ca2+ in the soil after harvest. Content of NH4-N in the soil also increased after the rotation of soybean than the continuous rice cropping in the soil during the rice growth period. These chemical change in the soil caused to increase rice growth in number of the panicles and the spikelet per square meter. The yield of rice was increased by the rotation with soybean, and was gradually increased in the triennial rotation of soybean and rice. But the yield of soybean was decreased in continuous cultivation for two or three years in the paddy field. It was recommended for annual rotation to prevent the yield of soybean from decrease.

This study is to describe continuous-flow analysis (CFA) for the determination of nitrate using hydrazine-copper in plant material and to test precision of this method compared with that of methods, which are RQflex method and salicylic acid method. Samples were leaves of watermelon, cucumber, melon and tomato. Nitrate values measured by the RQflex method were greater than those measured by CFA or salicylic acid method. The correlation of nitrate values between those measured by CFA and salicylic acid method was , and those measured by CFA between those measured by RQflex method was . Recovery rate of nitrate added to tissue extract by CFA method was .

This study was carried out to investigate the changes in soil chemical properties and yields of crops by rice-soybean rotation cropping system at silt loam soil. There were 4 rotation cropping systems; continuous rice cultivation, annual, biennial and triennial rotation of soybean and rice. There were little change in pH, organic matter, and contents with decrease in available phosphate content in the continuous rice cropping. The cropping system of soybean-rice caused to increase in available , and in the soil after harvest. Content of in the soil also increased after the rotation of soybean than the continuous rice cropping in the soil during the rice growth period. These chemical change in the soil caused to increase rice growth in number of the panicles and the spikelet per square meter. The yield of rice was increased by the rotation with soybean, and was gradually increased in the triennial rotation of soybean and rice. But the yield of soybean was decreased in continuous cultivation for two or three years in the paddy field. It was recommended for annual rotation to prevent the yield of soybean from decrease.

For better management of micronutrients in crop cultivation, the availability of micronutrients in the soils must be updated and evaluated as a first step. This study was conducted to investigate the distribution of micronutrients in soils of plastic film houses. Total 396 soil samples were collected from the plastic film houses of various crops in Yeongnam province (strawberry, 96; red pepper, 66; tomato, 74; oriental melon, 97; cucumber, 63). Total and available contents of B, Cu, Zn, Fe, and Mn in the soils were determined. Available B was extracted with hot water and available Cu, Zn, Fe, and Mn were extracted with 0.1 N HCl. Mean values of total contents of B, Cu, Zn, Fe, and Mn in the plastic film house soils were 25, 32, 74, 21,316, and , respectively. Total contents of micronutrients in the plastic film house soils were similar to those found in the open fields nearby, while they were different among the locations investigated. Mean contents extractable B, Cu, and Zn in the plastic film house soils were 2.1, 7.5, and , respectively. The contents of extractable B, Cu, and Zn in the plastic film house soils were higher than those found in the open fields nearby with exceptions of B in soils of strawberry and Cu in soils of red pepper and oriental melon. However, mean contents of extractable Fe and Mn in the plastic film house soils were 156 and , respectively, and the mean content of extractable Fe was much lower than that found in open fields nearby. The contents of extractable Zn, Fe, and Mn were higher than the sufficient levels for the crop requirements in most of the plastic film house soils investigated. Contents of extractable Cu in most soils of strawberry, tomato and cucumber cultivations were higher than the sufficient level. However, extractable Cu contents were below the sufficient level in about 30% of investigated soils of red pepper and oriental melon cultivation. Soils containing higher contents of extractable B than the sufficient level were relatively fewer in comparison to the other micronutrients.

Utilization of organic by-product fertilizers has many beneficial effects on agricultural activities and in aspects of the disposal of enormous amounts of livestock manure. Most of these beneficial effects are related to the improvement of soil condition, such as fertility status and physicochemical quality of soil. But, appropriate indexes are needed to effectively manage the quality of organic by-product fertilizers amended on soil. To find chemical and physical standard to control the compost quality, the changes in chemical and physical characteristics of organic by-product fertilizers during composting were investigated, and also an appropriate physical method for this end. The results showed chemical properties, such as humic acid content, OM/N ratio, cation exchange capacity and salt content, had significant relationships during the composting. The water content, particle and bulk densities, particle size and color indices, as physical properties, were also applicable factors for the quality control of compost.

The objective of this study was to evaluate the effects of the application of compost on the availability of micronutrients in lettuce. Micronutrient contents of manure-based composts containing various other source materials were investigated. Total and extractable contents of micronutrients in the composts were analysed. Pots containing soil of relatively low micronutrient levels were treated with 1,000 and of compost and used to grow lettuce plants under greenhouse conditions. Fresh and dry weights of lettuce and micronutrient uptake were determined after harvest. Manure-based composts of various other source materials contained very different amounts of total and extractable micronutrients. Total contents of B, Cu, Fe, Mn, Mo and Zn were in the range of 26-42, 27-160, 4,300-9,500, 290-790, 0-0.5 and , respectively. The contents of 0.1 N HCl extractable B, Cu, Fe, Mn and Zn were 23-32, 1.3-2.6, <1, 7-32 and 0.5-5% of total content, respectively. Contents of micronutrients extractable in DTPA solution were generally higher than those extractable in 0.1 N HCl. It was found that the fresh and dry matter productions of the plants were significantly higher in the compost treatment of . Lettuce grown in soil treated 1,000 and of manure-based compost contained higher levels of B, Cu, Mo and Zn than lettuce grown without compost application. However, contents of Fe and Mn in lettuce were relatively lower in the compost treatments. In the compost treatments the proportions of micronutrients in soil and plant were all in the optimum ranges and below the toxicity levels. The results obtained allow us to establish that commercial composts could be used as soil amendment for plastic film house crop production with sufficient supply of micronutrients.

The SMG project has been driven to secure food and water resources by closing of the SMG dyke for the preparation of the unification of Korean peninsular. It was investigated for pollution loads, land use distribution and water consumption for environmental assessments in two watersheds, the Mankyeong River (MK) and the Dongjin River (DJ) to assess the role of agricultural land on the alleviation of pollution loads to the SMG basin. It is needed to give the priority in managing pollution sources to conserve freshwater in the Saemangeum (SMG) basin after the completion of the SMG reclamation from tideland. The MK has water of which 14.1% were used for living, 73.6% for agriculture and 12.3% for industry. The DJ has water of which 3.0% for living, 94.5% for agriculture and 2.5% for industry. As compared to proportion of each land of total area, agricultural land was 1.4 times larger, livestock farming 7 times larger, forest 0.74 times smaller, and built-up area 0.67 times smaller in DJ watershed than in MK watershed. Pollution sources in MK and DJ watersheds were originated at a higher proportion from population including the sewage disposal and a livestock farming area rather than from the land. Water consumption and land use distribution influenced the water quality of the rivers; DJ watershed had far lower value of electric conductivity, , TN and TP than MK watershed. A large proportion of paddy field also influenced to reduce pollute loadings after rainfall; DJ watershed, which has a relatively large area of paddy fields, had a far lower delivery load after rainfall than MK watershed even though DJ watershed had large livestock farming area. As paddy fields was irrigated by Iksancheon water, 37% of nitrogen, 50% of phosphates and 14.0% of was removed by the paddy field just after flowing 150 meter, and rice plants could remove TN 100.0 kg, 24.0 kg, and 119.2 kg per hectare at harvest by irrigation of Iksancheon water. Conclusively, rice paddy fields played a positive role to conserve the water quality in the Iksancheon watershed.